Pneumatic action



E. H. DODDS.

PNEUMATIC ACTION.

APPLICATION FILED OCT. 24.19l9.

1,388,41 3', Patented Aug. 23, 1921.

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UNITED STATES PATENT OFFICE.

EDGAR HENRY borne, on cnoucn mnrnnnon, ENGLAND.

To all whom it may concern:

7 Be itlmown that I, EDGAR HENRY Donns, subject of the King of Great Britainjand Ireland, residing at 26 Tri'nder road. Crouch Hill, in the county of London, England, have invented certain new and useful Improvements in Pneumatic Actions. of which the following is, a specification.

My invention relates to improvements in pneumatic actions for automaticmusical instruments, piano players and the likeof the typeemployingpneumatic valve mechanismfor operating the instrument action.

.The primaryobject of my invention is to provide a pneumaticyalve action which can be cheaply manufactured. v

A further object. of my inyentionis to construct as self contained units. valves and covers which can be detachably secured to valve casings suitably constructed with two open sides for the reception of such units.

A further object of my invention is to construct a valve action wherein the valve rFigure 1 is a sectionthrough the valve mechanism and striking pneumatic, the latter' being shown partly in elevation. Fig. 2 is a similar view showing the valve in a different position. i

Fig. 3 is a plan yiewof Fig.1.

Fig. 4.- is a perspective view of; one form of single double acting valve. v

Figs. 5 and 6, are side elevation andtransverse sectionrespectively of a modified form of valve. H V Y The valve casing 1 may be formed during manufacture with two open sides for con-v veniencein fitting the valve.

These opensides are. ad pted to be closed by a cover plateconyeniently comprisingan L-shaped metal plate 2secured firmly to the valve casing-in an air tight manner prefer ably by the use of suitable interposed packmg. This cover plate is provided with an an port or aperture 3 and 4 respectively in each face forming valve seatings for adouble'acting-flap valve 5, This valve com- 7 I prisesv in the form. shown in Figs. 1-4 in- PNEUMATIG ACTION.

7 Specification of Letters latent. Patented Aug. 23, 1921. Application filed October 24, 1919. Serial No. 333,056.

elusive an L-shaped metalmember formed with two arms extending at right angles or at approximately right angles to one another and is provided at or near the point of connection of said arms with laterally roiecting pivot pins 6 which pins are supported in suitable bearings orbrackets 7 at the junction of the two sides of the cover plate 2. The two opposite walls 1'? (Fig. 3) of the casing 1 may if desired act as a distanc-v ing medium for the pivot pin 6 to prevent lateral displacement of the valve. The arms of the valve member provide valve heads which are of such dimensions as to completely cover their respective ports3 and 4; in the member 2 and their angular arrangement relative to said ports is such that while one valve is closed the other will be open. The facesof the arms are preferably furnished with facings 8 of leather or the like for efiicient action.

The casing 1 has formed therewith or secured thereto, the usual bellows or striking pneumatic 9 and is preferably arranged to extend in a horizontal position, the horizontally disposed. port 4.,communicating with the atmosphere while the port 3 situated in the vertical wall of the member 2 communicates with a chamber 10 connected to the suction or wind chest. Under normal conditions the upper valve head will be off its seating and open and'its weight is sufficient to maintain the vertically disposed valve head in its closed position. 7

.The casing 1 carrying the pneumatic 9' i may conveniently be connected to the chamber 10 by brackets 11, or the casing l'may be extended on eachside in the, neighborhood of the hinged end of the pneumatic to receive screws'or the like for securing the casing to the chamber 10. By this means the pneumatic and its associated valve action may be readily removed as a single unit for mspectlon'or repair and is easily replaced.

The wind chest 10 is provided with perforations oriports 11 arranged one to each valve action and providing direct communication between the wind chest and the port 3. Located opposite the port 3 is a chamber 12 separated from thewind chest 10 b a d1 a hragm 13. This diaphragm is formed wit a tappet rod or sliding pin 14 proiect ing through the perforations or port 11 in the wind chest, its extremity normally lying adjacent to but clear of the vertically disposed head of the valve 5. This rod is preferably guided in a bracket or the like 15 secured to the inner face of the valve chest. The chamber 12 has communicatinotherewith the port 16 having fixed therein a tube 17 to receive the usual flexible tube or conduit communicating with one of the apertures in the tracker bar. The port 16 also communicates through a small by-pass 0r port 18 with the wind chest. 19 is a port connecting the interior of the valve casing and the pneumatic 9. I V i In the construction shown in Figs. 5 and 6 the valve is constructed of two members 20 and 21 respectively consisting of flexible material such as leather, felt, thin sheet steel or the like secured in a convenient manner to the point of connection of the sides of the L shaped cover plate 2. The rear of the members 20 and 21 have secured thereto plates 22 and 23 respectively of metal or other rigid material said plates being lo cated so as to register with their respective port 3 and 1. The plate 23 has fixed thereto a block Qtfrom which extends a curved or quadrant shaped adjusting screw 25 the outer free end 25 of which extends toward the plate 22 secured to the rear of the valve member 20. This end of the adjusting screw is adapted to receive a screwed nut 26 which may be conveniently formed of leather or the like. This construction permits the length of the are between the valve heads formed by the members 20 and 21 to be adjusted. It will be readily understood that ifnecessary that each of the members 20 and 21 may be made of metal or other non-flexible material, each member being separately pivoted or connected to the cover plate 2.

The operation is as follows Suction is produced in the usual manner by rarefaction of air in the wind chest or suction chest 10 by pedal or other mechanism. Now assuming. the music roll in such position'that it is obstructing any of the vents in the tracker bar, the diaphragms associated with these closed vents will remain substantially stationary so long as the conditions in their chambers are normal or not changed. The reduction of air pressure in the wind chest will however cause the verti= cal valve head of the valve 5 which in this construction constitutes the primary valve, to be drawn more firmly on its" seating so as to close the port 3 while the co-acting valve is open to the atmosphere through the port 4 which is of higher pressure than the air on the wind chest. In this mannerno suction takes place in the strikingpneumatic 9 which therefore remains stationary in its extended and inoperative position. Now upon any of the perforations in the tracker bar being opened by the perforations in the music roll registering therewith, the associated diaphragms will be drawn forward. This will effect a sliding movement of the tappet rods 14: secured to the diaphragms 13 which will thereupon'engage the primary valve to force the same open and simultaneously close the port 4 to the atmosphere. Communication is thus freely provided between the suction chest 10 and the pneumatic 9 which will thus be exhausted and collapsed and operating the corresponding key or actuating mechanism. A valve mechanism and striking pneumatic as hercinbefore described being provided to-each key of the instrument, the operations are obviously continued to strike the different notes as long as theinstrument is under operation.

It is preferable to provide thesmall bypass or passages 18 between each diaphragm chamber 12 and the wind chest 10. which while not materially interfering with efficient action, insures the diaphragms remaining in their inoperative positions by providing suction at their rear while the perforations in the tracker bar are closed.

The size and shape of the valve. heads and the air ports may be varied as desired and I prefer in actual practice to have a cranked pivotal connection for the valve heads (Figs. 1 we), so that these open in a more direct manner to increase the clearance-and close with good effect.

It will be appreciatedthat a valve action constructed according to the invention requires no tortuous wind passage so that the action is more direct, resulting in better repetition.

Further owingto the simplicity of the design the pneumatic can be arranged in the action in a very compact manner with the necessary striking distance between each and thus effect a considerable economy in space with ease of removal or mounting when desired.

What I claim as my invention and desire to obtain by Letters Patent is 1. A pneumatic valve action comprising in combination a valve casing, including two open sides closed by a detachable L-shaped cover of metal, a single double-acting valve pivotally mounted to the angle of said cover, said valve being formed with two sides forming valve heads extending approximately at right angles to one another, and air ports or apertures in the walls of said cover with which said valve heads cooperate.

2. A pneumatic valve action comprising in combination a valve casing, including two side walls and two open sides closed by an L-shaped cover of metal, a single doubleacting valve pivotally mounted to the angle of said cover, said valve being formed with two sides forming valve heads extending approximately at right angles to one another,

laterally extending pivot pins at the junction of said sides, said pins engaging said side walls, and air ports or apertures in the walls of said cover with which said valve 5 heads coeperate.

3. In a neumatic valve action, the combination oi a valve casing having two open sides closed by a metal member of L section, a double acting valve pivoted to the angle of said member, a wind chest, flanges on 10 said casing, securing means passing through said flanges, and engaging with said chest.

EDGAR HENRY DODDS. 

